特大型洞室过浅埋段的开挖与支护

Excavation and Support of the Shallow-buried Section of Extra-large Tunnel

泸定水电站2号泄洪洞为特大断面洞室,具有开挖断面大、跨度宽、地质条件复杂等特点,特别是浑水沟段垂直埋深小(最小岩层埋深为6 m)。根据地质勘探资料及现场地表勘查情况,通过对该段采用地表处理与洞室内处理相结合的手段,顺利完成了该洞室的开挖、支护,确保了洞室按期过流,为工程顺利进行奠定了良好的基础。

The No. 2 spillway tunnel in Luding Hydropower Station is a tunnel with extra-large section. The excavation section is large and wide, and the geological condition is complex. The section of the tunnel passing through the Hunshui Ditch is especially shallow-buried with a smallest rock embedded depth of 6m. Based on the geological information and field survey, the surface and tunnel treatments are combined to deal with the problem. The treatments ensure the successful excavation and support, on schedule.